Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease globally, affecting approximately 25% of the general population. NAFLD occurs in the absence of excessive alcohol consumption and is closely associated with metabolic syndrome (MetS) and its components.
Author, Year | Study Name (If Any) | Study Design | Country | Age—Category | Study Sample | NAFLD Diagnosis | Cognitive Function Assessment | Main Exposure | Main Outcome | Level of Association | Conclusion |
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Liu, Q., 2022 | - | prospective | China | middle-aged and older people | 1651 | Abdominal ultrasonography | Mini-Mental State Examination (MMSE) | NAFLD presence | Global cognitive function | 4-year prospective association | NAFLD associated with cognitive decline, especially in middle-aged and with carotid stenosis population. |
Gerber, Y., 2021 | CARDIA study | prospective | USA | middle-aged | 2809 | Computed tomography (CT) examination | Battery of 3 cognitive tests: Digit Symbol Substitution Test (DSST), the Rey Auditory Verbal Learning Test (RAVLT), and the Stroop Test | NAFLD presence | Scores in cognitive tests | Cross-sectional/5-year prospective association | NAFLD presence associated with lower cognitive performance/NAFLD presence not significantly associated with cognitive decline in 5-year follow-up. |
Labenz, C., 2021 | - | prospective | Germany | older people | 22,317 patients/22,317 controls | ICD-10 coding | Dementia | NAFLD presence | Dementia risk | 10-year prospective association | No independent association with dementia incidence was detected. |
Shang, Y., 2021 |
- | nested case-cohort | Sweden | middle aged and older people | 656 | Liver Biopsy | Dementia | NAFLD presence | Dementia risk | 20-year prospective association | No association between NAFLD and dementia risk in an almost 20-year follow-up. Histological markers to a conventional risk model for dementia enhanced its predictive ability. |
Solfrizzi, V., 2020 | Italian Longitudinal Study on Aging | prospective | Italy | older people | 1061 | NAFLD fibrosis score (NFS) | Dementia | NFS categorization | Dementia risk | 8-year prospective association | Advanced liver fibrosis (F3-F4 NFS) could be a long-term predictor for overall dementia risk. |
Weinstein, G., 2019 | Framingham | prospective | USA | middle-aged and older people | 1287 | Multi-detector computed tomography scans | Neuropsychological test (Wechsler Memory Scale) | NAFLD presence | Logical Memory Delayed Recall (LMd); Visual Reproduction Delayed Recall (VRd); Trail making B minus Trail making A (TrB-TrA); Similarities test (SIM); Hooper Visual Organization test (HVOT) | Cross-sectional | NAFLD per se not associated with cognitive performance. Advanced fibrosis associated with poorer performance on tests assessing executive function and abstract reasoning. |
Weinstein, A. A., 2018 | NHANES | cross-sectional | USA | >65 years old | 1102 | Fatty liver index score ≥ 60 | Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-WL); Animal Fluency Test; digit symbol substitution test | NAFLD presence | Scores in cognitive tests | Cross-sectional | NAFLD with or without type 2 diabetes performed significantly worse on a task that requires a combination of processing speed, sustained attention, and working memory. |
Filipović, B., 2018 | - | cross-sectional | Serbia | middle-aged | 76 | Ultrasonography (US) | MRI brain scanning combined with Montreal Cognitive Assessment (MoCA) test | NAFLD presence | MoCA score | Cross-sectional | NAFLD significantly influenced cognitive deficit and tissue volume reduction and people suffering from NAFLD had about four times higher risk of having a cognitive impairment. |
Tuttolomondo, A., 2018 | - | case-control | Italy | middle-aged | Control: 83/Cases: 80 | Liver biopsy; ultrasonography (US); liver stiffness | Mini-Mental State Examination (MMSE) | NAFLD presence | Global cognitive function | Cross-sectional | NAFLD subjects lower mean MMSE scores in comparison with control subjects without NAFLD. |
Weinstein, G., 2018 | Framingham | prospective | USA | older people | 766 | Multi-detector computed tomography scans | Brain magnetic resonance imaging | NAFLD presence | TCBV (years of brain aging) | Cross-sectional | NAFLD associated with brain aging. |
Elliot, C., 2013 | - | nested case-cohort | USA | middle aged and older people | 224 | Histological diagnosis | Cognitive Failures Questionnaire | NAFLD presence | frequency of cognitive slips or failures occurring in everyday life |
Cross-sectional | NAFLD patients presented worse function independently associated with cognitive symptoms, compared with their age-matched controls. |